Blisters are usually happening if you walk much more than you are used to, or the shoes are much harder than those you usually wear. For example on multi-day trekkings in heavy trekking shoes. The people more used to walking have usually harder feet and are much less likely to get blisters.
The usual prevention solution is to walk as much as possible in the shoes you are going to trek in before the trek. But I wander if walking barefoot hardens the feet in the way that will prevent blisters as well? The skin must be much harder, if you walk barefoot, so it would be logical to suppose such feet will be better protected against friction in shoes.
However, when walking barefeet, the friction comes from the bottom. In shoes, there's also a friction in the places shoes fold, near the ankles etc.
